[en] Controlled radical polymerization (CRP) is a valuable strategy to design a large range of polymers with well defined molecular characteristics under non very demanding conditions. However, the known CRP techniques, such as nitroxide mediated polymerization (NMP), atom transfer radical polymerization (ATRP) and radical addition-fragmentation chain transfer polymerization (RAFT), suffer from limitations, including a moderate control on the vinyl acetate polymerization. Within the search for new controlled radical polymerization processes, we designed a system based on the reversible combination of growing macroradicals with a cobalt(II)acetylacetonate complex which provides an effective control of the vinyl acetate polymerization even when carried out in suspension in water. In a macromolecular engineering
effort, well-defined end-functional poly(vinyl acetate), and poly(vinyl acetate) or poly(vinyl alcohol) containing block copolymers have been synthesized.